(Reuters) - Hurricane Irma is expected to move near or over portions of the northern Leeward Islands on Tuesday night and early Wednesday, the U.S. National Hurricane Center (NHC) said.

Irma, a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale, is about 410 miles (660 km) east of the Leeward Islands with maximum sustained winds of 140 miles per hour (220 kmh), the NHC said.

It is forecast to strengthen further during the next 48 hours and a hurricane warning has been issued for Puerto Rico and the Virgin Islands.